Enclosures or covers for open-bed vehicles, such as camper tops for pick-up trucks, are well known and have become increasingly popular. Camper tops are generally categorized as being of the walk-in type or of the low profile type.
The walk-in tops usually provide adequate head room to accommodate an average sized person in an up-right position. Access to the truck bed is generally through a door or opening at the rear of the pick-up truck. Wind resistance, excessive bulkiness and weight, poor roadability and bed accessibility, difficulties in removing and installing, adverse fuel consumption, etc., are included amongst the major disadvantages which have substantially diminished the popularity of the walk-in type camper tops.
Low profile camper tops typically have a roof-line approximating the height of the passenger cab. They have become increasingly popular since their design and construction alleviates many of the problems attendant to the walk-in camper tops. Unfortunately, the head room and interior accessibility particularily in the foremost areas of the bed are severly limited by the low profile design.
Open bed vehicles such as pick-up truck beds, typically comprise a pair of upwardly extending sidewalls, a front wall (which may be a separate partition or a part of the outside rear wall of the passenger cabin) and a rear hitch or gate which forms the back wall of the bed. Camper tops are essentially a vertical extension of the bed walls with a roof or top covering. The camper top backwall is typically equipped with a hinging, and locking mechanism. Access to the vehicle bed is most commonly achieved by upwardly swinging the back wall of the camper and the downward swinging of the end gate.
The eariler versions of the camper tops were rigidly secured (by bolts, clamps, etc.) to the bed of the pick-up vehicle. Access to the pick-up bed was severly limited by single entry through the back wall.
The art has proposed numerous devices to improve upon access. Numerous devices affording selective access to open beds have been proposed. For example, U.S. Pat. No. 4,101,162 by Koehm proposed a vertically swingable camper shell. The shell relies upon a custom made and complicated hinging mechanism positioned near the passenger cab. This device improves upon the rear accessibility to but forward accessibility remains limited.
Other devices, embodying a horizontally swingable camper top design, afford access to the side of the pick-up bed. Included amongst such devices is a detachable camper top disclosed in U.S. Pat. No. 2,886, 375 by Crawford. The Crawford patent relies upon cam hooking members affixed to axially rotatable shafts rigidly secured to the sidewalls of the bed. The custom made camper top sidewalls are fitted with matching rollers for engaging the cam hooking members. The cam hooking members may be disengaged from the matching rollers by rotating the shaft. The camper top may then be pivoted upon the engaged cam hooking members and rollers on the opposite side of the bed. The Crawford device is expensive, and structurally complicated and requires custom manufacturing of the roller system into the camper top shell.
Another variation of a horizontally swingable hinging mechanism may be found in U.S. Pat. No. 3,180,674 by Pounds. The Pounds device contains post-carrying plates which fit into the stake pockets. These plates are hinged to the sidewalls of the camper top. Another horizontally hinged device for a pick-up vehicle is disclosed in U.S. Pat. No. 4,142,760 by Dockery, et al. The Dockery, et al., device comprises a base member equipped with a hinging mechanism similar to a conventional doorway hinges. Similar to the hinging effect of a doorway, horizontal swingability of the bed cover is limited to hinge placement.
A still further hinging device is disclosed in U.S. Pat. No. 4,284,303 by Hather. The Hather hinging mechanism comprises a plurality of slotted eyelets affixed to the bed sidewall with a plurality of complementary mating slots in a rotatable shaft affixed to the camper top sidewall. Access to either side of the bed may be achieved by rotating the shaft on the desired side of access so that the shaft slots align with the corresponding eyelets. This permits the shaft to be lifted through the eyelet and the camper cover may then be swung upon the hinge formed by the engaged eyelets and shaft of the opposite sidewall.
A hinging device for converting a pick-up truck bed into a flat bed is disclosed in U.S. Pat. No. 4,181,351 by Spanke. The Spanke device entails a plurality of eyelet members secured to support rail fo the bed and a plurality of pins which when inserted into the eyelets, provide means for securing and/or swinging the bed upon the axis formed by the eyelet and the pin insertions.
As evidenced by the aforementioned patented literature, numerous hinging devices for achieving selective access to the bed have been proposed. Each proposal proports to overcome certain prior art deficiencies. Many of the proposed devices embody complex and bulky structural components which are impractical from both a manufacturing and field usage view point. Others involve complicated and multi-staged procedural steps for inserting, removing, or achieving selective access to the bed. A majority of the proposed hinging devices necessitate substantial alterations to the design and construction of the camper top and/or bed. Such proposals generally necessitate tailoring or custom manufacturing of the camper shell so as to fit the hinging device rather than a hinging mechanism which may be readily adapted to the commonly available, mass produced camper tops or enclosure shells of the trade. Such proposals cannot be reconciled with the long-standing industrial and consumer objectives of providing a high quality, mass unit manufacture at a low cost. Certain proposals have relied upon externally exposed components and a separate key locking means as opposed to a device which would be compatable with the conventional single key-locking system of the presently available camper tops. A hinging mechanism which would permit disengagement within the internal confines of the pick-up bed and rely upon the cam camper top key-locking system would represent a significant improvement.